1 //===- SubtargetFeature.cpp - CPU characteristics Implementation ----------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the SubtargetFeature interface.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/MC/SubtargetFeature.h"
15 #include "llvm/Support/Debug.h"
16 #include "llvm/Support/raw_ostream.h"
17 #include "llvm/ADT/StringExtras.h"
24 //===----------------------------------------------------------------------===//
25 // Static Helper Functions
26 //===----------------------------------------------------------------------===//
28 /// hasFlag - Determine if a feature has a flag; '+' or '-'
30 static inline bool hasFlag(const StringRef Feature) {
31 assert(!Feature.empty() && "Empty string");
32 // Get first character
34 // Check if first character is '+' or '-' flag
35 return Ch == '+' || Ch =='-';
38 /// StripFlag - Return string stripped of flag.
40 static inline std::string StripFlag(const StringRef Feature) {
41 return hasFlag(Feature) ? Feature.substr(1) : Feature;
44 /// isEnabled - Return true if enable flag; '+'.
46 static inline bool isEnabled(const StringRef Feature) {
47 assert(!Feature.empty() && "Empty string");
48 // Get first character
50 // Check if first character is '+' for enabled
54 /// PrependFlag - Return a string with a prepended flag; '+' or '-'.
56 static inline std::string PrependFlag(const StringRef Feature,
58 assert(!Feature.empty() && "Empty string");
61 std::string Prefix = IsEnabled ? "+" : "-";
66 /// Split - Splits a string of comma separated items in to a vector of strings.
68 static void Split(std::vector<std::string> &V, const StringRef S) {
72 // Start at beginning of string.
75 // Find the next comma
76 size_t Comma = S.find(',', Pos);
77 // If no comma found then the rest of the string is used
78 if (Comma == std::string::npos) {
79 // Add string to vector
80 V.push_back(S.substr(Pos));
83 // Otherwise add substring to vector
84 V.push_back(S.substr(Pos, Comma - Pos));
85 // Advance to next item
90 /// Join a vector of strings to a string with a comma separating each element.
92 static std::string Join(const std::vector<std::string> &V) {
93 // Start with empty string.
95 // If the vector is not empty
97 // Start with the first feature
99 // For each successive feature
100 for (size_t i = 1; i < V.size(); i++) {
107 // Return the features string
112 void SubtargetFeatures::AddFeature(const StringRef String,
114 // Don't add empty features
115 if (!String.empty()) {
116 // Convert to lowercase, prepend flag and add to vector
117 Features.push_back(PrependFlag(LowercaseString(String), IsEnabled));
121 /// Find KV in array using binary search.
122 template<typename T> const T *Find(const StringRef S, const T *A, size_t L) {
123 // Make the lower bound element we're looking for
126 // Determine the end of the array
128 // Binary search the array
129 const T *F = std::lower_bound(A, Hi, KV);
130 // If not found then return NULL
131 if (F == Hi || std::string(F->Key) != S) return NULL;
132 // Return the found array item
136 /// getLongestEntryLength - Return the length of the longest entry in the table.
138 static size_t getLongestEntryLength(const SubtargetFeatureKV *Table,
141 for (size_t i = 0; i < Size; i++)
142 MaxLen = std::max(MaxLen, std::strlen(Table[i].Key));
146 /// Display help for feature choices.
148 static void Help(const SubtargetFeatureKV *CPUTable, size_t CPUTableSize,
149 const SubtargetFeatureKV *FeatTable, size_t FeatTableSize) {
150 // Determine the length of the longest CPU and Feature entries.
151 unsigned MaxCPULen = getLongestEntryLength(CPUTable, CPUTableSize);
152 unsigned MaxFeatLen = getLongestEntryLength(FeatTable, FeatTableSize);
154 // Print the CPU table.
155 errs() << "Available CPUs for this target:\n\n";
156 for (size_t i = 0; i != CPUTableSize; i++)
157 errs() << " " << CPUTable[i].Key
158 << std::string(MaxCPULen - std::strlen(CPUTable[i].Key), ' ')
159 << " - " << CPUTable[i].Desc << ".\n";
162 // Print the Feature table.
163 errs() << "Available features for this target:\n\n";
164 for (size_t i = 0; i != FeatTableSize; i++)
165 errs() << " " << FeatTable[i].Key
166 << std::string(MaxFeatLen - std::strlen(FeatTable[i].Key), ' ')
167 << " - " << FeatTable[i].Desc << ".\n";
170 errs() << "Use +feature to enable a feature, or -feature to disable it.\n"
171 << "For example, llc -mcpu=mycpu -mattr=+feature1,-feature2\n";
175 //===----------------------------------------------------------------------===//
176 // SubtargetFeatures Implementation
177 //===----------------------------------------------------------------------===//
179 SubtargetFeatures::SubtargetFeatures(const StringRef Initial) {
180 // Break up string into separate features
181 Split(Features, Initial);
185 std::string SubtargetFeatures::getString() const {
186 return Join(Features);
189 /// SetImpliedBits - For each feature that is (transitively) implied by this
193 void SetImpliedBits(uint64_t &Bits, const SubtargetFeatureKV *FeatureEntry,
194 const SubtargetFeatureKV *FeatureTable,
195 size_t FeatureTableSize) {
196 for (size_t i = 0; i < FeatureTableSize; ++i) {
197 const SubtargetFeatureKV &FE = FeatureTable[i];
199 if (FeatureEntry->Value == FE.Value) continue;
201 if (FeatureEntry->Implies & FE.Value) {
203 SetImpliedBits(Bits, &FE, FeatureTable, FeatureTableSize);
208 /// ClearImpliedBits - For each feature that (transitively) implies this
209 /// feature, clear it.
212 void ClearImpliedBits(uint64_t &Bits, const SubtargetFeatureKV *FeatureEntry,
213 const SubtargetFeatureKV *FeatureTable,
214 size_t FeatureTableSize) {
215 for (size_t i = 0; i < FeatureTableSize; ++i) {
216 const SubtargetFeatureKV &FE = FeatureTable[i];
218 if (FeatureEntry->Value == FE.Value) continue;
220 if (FE.Implies & FeatureEntry->Value) {
222 ClearImpliedBits(Bits, &FE, FeatureTable, FeatureTableSize);
227 /// getFeatureBits - Get feature bits a CPU.
229 uint64_t SubtargetFeatures::getFeatureBits(const StringRef CPU,
230 const SubtargetFeatureKV *CPUTable,
232 const SubtargetFeatureKV *FeatureTable,
233 size_t FeatureTableSize) {
234 assert(CPUTable && "missing CPU table");
235 assert(FeatureTable && "missing features table");
237 for (size_t i = 1; i < CPUTableSize; i++) {
238 assert(strcmp(CPUTable[i - 1].Key, CPUTable[i].Key) < 0 &&
239 "CPU table is not sorted");
241 for (size_t i = 1; i < FeatureTableSize; i++) {
242 assert(strcmp(FeatureTable[i - 1].Key, FeatureTable[i].Key) < 0 &&
243 "CPU features table is not sorted");
246 uint64_t Bits = 0; // Resulting bits
248 // Check if help is needed
250 Help(CPUTable, CPUTableSize, FeatureTable, FeatureTableSize);
253 const SubtargetFeatureKV *CPUEntry = Find(CPU, CPUTable, CPUTableSize);
254 // If there is a match
256 // Set base feature bits
257 Bits = CPUEntry->Value;
259 // Set the feature implied by this CPU feature, if any.
260 for (size_t i = 0; i < FeatureTableSize; ++i) {
261 const SubtargetFeatureKV &FE = FeatureTable[i];
262 if (CPUEntry->Value & FE.Value)
263 SetImpliedBits(Bits, &FE, FeatureTable, FeatureTableSize);
267 << "' is not a recognized processor for this target"
268 << " (ignoring processor)\n";
270 // Iterate through each feature
271 for (size_t i = 0, E = Features.size(); i < E; i++) {
272 const StringRef Feature = Features[i];
275 if (Feature == "+help")
276 Help(CPUTable, CPUTableSize, FeatureTable, FeatureTableSize);
278 // Find feature in table.
279 const SubtargetFeatureKV *FeatureEntry =
280 Find(StripFlag(Feature), FeatureTable, FeatureTableSize);
281 // If there is a match
283 // Enable/disable feature in bits
284 if (isEnabled(Feature)) {
285 Bits |= FeatureEntry->Value;
287 // For each feature that this implies, set it.
288 SetImpliedBits(Bits, FeatureEntry, FeatureTable, FeatureTableSize);
290 Bits &= ~FeatureEntry->Value;
292 // For each feature that implies this, clear it.
293 ClearImpliedBits(Bits, FeatureEntry, FeatureTable, FeatureTableSize);
296 errs() << "'" << Feature
297 << "' is not a recognized feature for this target"
298 << " (ignoring feature)\n";
305 /// Get scheduling itinerary of a CPU.
306 void *SubtargetFeatures::getItinerary(const StringRef CPU,
307 const SubtargetInfoKV *Table,
309 assert(Table && "missing table");
311 for (size_t i = 1; i < TableSize; i++) {
312 assert(strcmp(Table[i - 1].Key, Table[i].Key) < 0 && "Table is not sorted");
317 const SubtargetInfoKV *Entry = Find(CPU, Table, TableSize);
323 << "' is not a recognized processor for this target"
324 << " (ignoring processor)\n";
329 /// print - Print feature string.
331 void SubtargetFeatures::print(raw_ostream &OS) const {
332 for (size_t i = 0, e = Features.size(); i != e; ++i)
333 OS << Features[i] << " ";
337 /// dump - Dump feature info.
339 void SubtargetFeatures::dump() const {
343 /// getDefaultSubtargetFeatures - Return a string listing the features
344 /// associated with the target triple.
346 /// FIXME: This is an inelegant way of specifying the features of a
347 /// subtarget. It would be better if we could encode this information
348 /// into the IR. See <rdar://5972456>.
350 void SubtargetFeatures::getDefaultSubtargetFeatures(const Triple& Triple) {
351 if (Triple.getVendor() == Triple::Apple) {
352 if (Triple.getArch() == Triple::ppc) {
354 AddFeature("altivec");
355 } else if (Triple.getArch() == Triple::ppc64) {
358 AddFeature("altivec");